Axle Advice Requested

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by Fletch79, May 22, 2003.

  1. Fletch79

    Fletch79 Registered Member

    May 14, 2003
    Likes Received:
    Southern Wisconsin
    Hello, I have a '79 Blazer with a GM-Corp, 12 bolt, 8.875" ring with factory govern-loc. 160,000 miles.

    It sometimes gives a 'clunk' between forward and reverse, and a much more mild clunk taking off from a stop.
    I had hoped it needed U-joints, but I'm not that lucky.

    I took the cover off to look it over.
    First thing I noticed was that it was on with silicone, so who knows what's been monkeyed with.
    The yoke can rotate about 3/8" before the ring is engaged, so the backlash is screwed.
    The yoke will not move verticaly or lateraly, and it's not leaking oil.
    I flexed the planetary gears a little with a screwdriver; there's a fair amount of slop in the carrier.
    The Govern-loc works fine.

    I was contemplating a low-buck rebuild, but ran into a few snags.
    Can't find a carrier kit for the Govern-loc; only for open diffs.
    Looked into a Lock-Right, but National Drivetrain says the one for my axle is meant to go in an open diff and wont fit my carrier. So now it's all the way up to an Eaton unit.

    Do do the rebuild , I'm looking at:
    $140-$150 Ring and Pinion
    $80 -$100 Bearing/Seal/Shim kit
    $350 Eaton unit.

    I can ride on this one for long enough to make my decisions.
    Before I throw ~$600 at the GM-12 bolt, I figured that I'd ask the forum.

    Should I be looking to go a different route?
    Different axle?
    Different components?

    Advice and personal experience appreciated.

  2. BranndonC

    BranndonC 3/4 ton status

    Mar 18, 2002
    Likes Received:
    Anaheim, Ca
    i in no way can answer this for you, but all the info you gave us would really help in your profile also, maybe someone lives neat you and can better help you in person. just a heads up, the guys here really like a full profile /forums/images/graemlins/smile.gif
  3. Shaggy

    Shaggy 3/4 ton status

    Dec 15, 2000
    Likes Received:
    Los Banos, CA
    <font color="green"> To tell you the truth, I don't think that you have a whole lot to worry about right now. Some slop is pretty normal, especially with a Gov-Loc diff. If you think about how many parts mesh with other parts and the tolerances between them, that easily comes up with the slp that you feel. The clunk happens fairly often, you might look to make sure it isn't a loose t-case mount or something too, but even if it's in the diff, if there were no metal shavings or obviously worn parts I wouldn't concern myself with it.

    If you feel the need to start dumping money into it, I would suggest finding a heavier duty axle to start with, such as a 14 bolt semifloater if you want to stay with the 6 lug, or if you want to really go for it, a 14 bolt full floater. If you get the FF you'll need 8 lug outers for the front to match the lug count, since the FFs only come in 8 lug. This would cost you a bit more, but the 14 bolt is a whole lot stronger than the 12 bolt.

    As for the silicone on the diff cover, that is a common and often preferred method of sealing the cover. I've never used a gasket on any diff cover, and the biggest rearend shop in this city uses only silicone to seal diffs too. I've never had a leak doing it this way.</font>
  4. mudhog

    mudhog THEGAME Staff Member Super Moderator

    Nov 6, 2000
    Likes Received:
    portland oregon
    what do you intend on doing with your blazer do you wheel hard? if yes then just go with a 14ff you can get one for under $200 and it will be much stronger than your current 12bolt /forums/images/graemlins/thumb.gif the only bad thing is a 14ff is 8lug

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